Archive for September 15, 2013

Texas Astronomers Unravel 20-Year Dark Matter Mystery With New Computer Models

September 15, 2013 Leave a comment

Astronomers at The University of Texas at Austin believe they have discovered the answer to a 20-year debate over how the mysterious cosmic “dark matter” is distributed in small galaxies. Graduate student John Jardel and his advisor Karl Gebhardt found that the distribution, on average, follows a simple law of decreasing density from the galaxy’s center, although the exact distribution often varies from galaxy to galaxy. The findings are published today in The Astrophysical Journal Letters.

Dark matter is matter that gives off no light, but that astronomers detect by seeing its gravitational tug on other objects (like stars). Theories abound on what dark matter might be made of — unseen particles, dead stars, and more — but nobody knows for sure. Though mysterious, understanding the nature of dark matter is important, because it makes up most of the matter in the universe. The only way to understand how the cosmos evolved to its present state is to decode dark matter’s role.

For that reason, astronomers study the distribution of dark matter within galaxies and on even larger scales. Dwarf galaxies, in particular, make great laboratories to study dark matter, Jardel says, because they contain up to 1,000 times more dark matter than normal matter. Normal galaxies like the Milky Way, on the other hand, contain only 10 times more dark matter than normal matter.

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